Four-Stroke Dirt Bike, Dual Sport & ATV Tech Info on 4Strokes.com

Non-Model Specific Subcategories: Technical Info | Tips | Links

4-Stroke Carb Jetting Tricks - A 4-stroke engine is basically an air pump and the carb meters how much air and fuel goes in. By Chris

Airbox Mod - I noticed a crisper throttle response and the engine seemed to rev faster. By ThumperTD

Baja Designs Dual Sport Lighting Kit Schematic

Baja Designs Dual Sport Lighting Schematic (70KB gif) and Wiring Diagram (60KB gif). By Jeff Moon

Basic Dirt Bike Overhaul - Do this to your bike and be happy all year long. I charge pro racers big bucks for this and they keep coming back! By NOS

Bike Lift, Floor Jack Plate - A custom plate built for a common floor jack to convert it to a hydraulic bike lift. By Edward McCafferty

Bike Mounted Tire Irons - I drilled holes in my tire irons and bolted them on the frame of my XR650L where the buddy pegs were. By MarkN

Calculate Top Speed (Forums) - Calculate theoretical top speed for any dirt bike or ATV. By jg

Califoria Motorcycle Requirements (2.2MB PDF file) - CA Highway Patrol official document listing complete motorcycle codes.

Carburetor Jetting - Carb jetting can be easily understood if we understand the basic principles of carb and engine operation. Magazine Reprint

Carburetor Jetting Crossover - Keihin, Dynojet and Mikuni carburetor jetting crossover reference. By Troy

Carb Overview (Keihin) - The carb on your bike should perform suitably with the standard recommended settings under average load, climatic, and barometric conditions. By 4Strokes.com

Chain Guard Flap - Keep your chain lube off your wife's back! By HorseRider650

Conversion of Dirt Bikes for Street or Dual Sport Use

Converting Dirt Bikes for Street or Dual-Sport Use (Forums)

Crankcase Breather Mod - This case or crankcase breather mod can be done on any bike to allow the crankcase to breath better. By superhondaz50

Dirt Bike Horsepower Calculator - Calculate the approximate HP of a dirt bike if you know the bike and rider weight and ¼-mile time.

Dirt Bike Tire Sizing - Most dirt bike tires have numbers that indicate the tire width, aspect ration (height) and rim diameter.

Do-It-Yourself Dual Sport / Supermotard Helmet

Rider Made Dual Sport / Motard Helmet - Build your own Supermoto / Dual Sport helmet. By David Closs & The Morton's

DIY Dual Sport Kit - I'm so glad I didn't buy a dual sport kit because I did it myself for a fraction of the cost. By Stu

DIY Aluminum Frame Guards - Homemade aluminum frame guards for about $5 a set. By mpigg

DIY Rubber Frame Guards - They are much cheaper than factory or aftermarket metal frame guards. By Anthony Loh

DIY Keyed Ignition Switch (Forums) - Install a keyed ignition switch on a dirt bike that did not already have one. Topic by b_king

Dual Sport Conversion & Wiring Diagram - I converted my dirt bike to a dual sport over the winter and this is what I did. By Mark

Dual Sport Requirements Per State 6/07 - Minimum requirements for dual sport motorcycles in the US. 6/06 Ver, 7/98 Ver

Exhaust Header Wrap - Keep exhaust temps confined. By Ygrumyz

Emergency Cable Fix - A way to fix a cable if the end pulls off and you are miles away from civilization. By Randy Ressell

Exhaust dB Reducer - This may also work for other aftermarket exhaust systems to reduce noise level. By Ken

Fault Finding Flow Chart for Motorcycle Charging Systems

Fault Finding Chart for Charging Systems (88KB PDF file) - The most common fault in electrical systems is a bad connection. By Electrex

Fix a Cracked or Broken Case - The price of a new case can be horribly expensive and in most cases it can be fixed for a fraction of the cost. By Brian10

Fork Oil Adjustment - Drain the forks and then accurately set the initial oil level. Don't be afraid, it's really quite simple! By Michael Hetrick

Four-Stroke Starting Procedure - If the engine is cold it may help to turn the idle screw up slightly to aid in warm-up and give the engine a little extra fuel. By 4Strokes.com

Dirt Bike Headlight Protectors - Build an inexpensive headlight protector or guard for your dirt bike. By various individuals

Garage Door Opener for a Dual Sport - Integrate your spare garage door opener on your dual sport. By Jlutty650L

Gear Ratio Chart (13KB PDF file) - Countershaft and rear sprocket gear ratios. By 4Strokes.com

Gearing Calculator (42KB Excel file) - Calculate speeds (MPH & KPH) for primary and final (trans & sprockets) gearing, wheel size, and RPM. By Chris Helberg

Helmet Sizing - For AFX, AGV, Grex, Icon, M2R, MDS, Moose, Nolan, Suomy, Thor, and Z1R helmets.

DIY Conventional Fork Leg Protectors - Make your own PVC lower fork leg protectors. It's easy, cost less than a pack of smokes, and snap right on the fork legs. By NOS

How To Read Your Spark Plug - Here's how to check your jetting by reading the plug. Includes NGK part numbering PDF file. By 4Strokes.com

How To Set Up a Disc Type Exhaust System - Although meant for the XR600R and XR650L with a White Brothers E-series exhaust, this may help with setup of other disc type exhausts. By WB

Measurement of Exhaust Sound Levels of Motorcycles

Motorcycle Exhaust Sound Measurement (40KB PDF file) - SAE Standard for test procedure, environment and instrumentation for determining exhaust sound levels. By SAE Mc Committee

Motorcycle Storage Procedures - Items of a motorcycle that should be addressed before putting it up for winter or long-term storage. By Robb Nelson

Oil Drain Funnel - Why pay $20 for a special funnel when you can make your own for less than $2? By KingTutt

Painting Vinyl Seats - Are you tired of that old faded seat? Do you have a late 80's KLR with a color scheme designed by Kawasaki's watercraft department? By Dale Wagler

Plastic Restoration via Painting - It's no secret that dirt bike plastic fades and tanks yellow and lose decals as they age. After good advice, this is what I've found works well. By Edward Pinzel

Rear Fender Bag - Here is an inexpensive rear fender bag for dirt bikes that do not have a rear luggage rack. By Jlutty650L

BIY Rear Wheel Alignment Tool - Build a rear wheel alignment tool yourself out of some PVC pipe for just a couple of bucks! By Dave Morgan

Registration Decal Saver - No more destroyed registration stickers when you remove your fork legs for service! (may or may not be legal) By 4Strokes.com

Rim Lock / Bead Lock / Bead Stopper Installation - If you switched from Dual Sport type tires to full knobbies, chances are you will need to install a rim lock. By 4Strokes.com

Seat Cover & Graphics Installation - Sooner or later the graphics on your thumper are going to start looking ratty. By 4Strokes.com

Side Panel Skids - Teflon rods cut in half lengthwise then attached to the side panels with counter-sunk bolts. By motomonte

Spring Preload, Race Sag & Suspension Adjustments - Setting the proper race sag is important for competition use. By 4Strokes.com

Testing for a Suspected CDI Problem - The first thing to do is to look at all the wires in the electrical system and make sure the insulation is not worn through... By qadsan

Tire Removal and Installation Procedures (5 Versions) and Tips - By 4Strokes.com and various individuals

TopSpeed V2.1 (151KB ZIP file) - TopSpeed Calculator by KAMware. Calculates for the following parameters: engine, gearing, exhaust, cam lobe center, and horsepower.

Understanding a Basic Dirt Bike Suspension - There are a few basic forces at work in suspensions that must be understood before making successful changes. By NOS

What to Look for When Buying a Used Dirt Bike - There's a lot junk for sale and the best thing you can do to avoid buying someone elses trash is educate yourself. By Pete Marshall

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Non-Model Specific Subcategories: Technical Info | Tips | Links